Biodegradable packaging materials with enhanced oxygen barrier performance

Abstract

A biodegradable packaging material having excellent oxygen barrier performance is disclosed. The material includes a biodegradable polymeric structure and a barrier layer positioned on at least one surface of the structure, wherein the barrier layer is derived from a water-based coating composition comprising biopolymer and clay. The biodegradable structure may include homopolymer or copolymer of lactic acid-based monomers. Starch and protein may be used as biopolymers. Clay in the disclosed coating composition may be at least partially exfoliated, have a particle size in range of nanometers, or both. When desired, the disclosed packaging material may include paper-based substrate having the barrier coated biodegradable polymer positioning on at least one of the paper-based substrate.

1 . A packaging material, including:
 (a) a biodegradable polymeric structure having opposite sides; and   (b) a barrier layer positioned on at least one side of the biodegradable structure, the barrier layer being derived from a water-based coating composition comprising a biopolymer binder and clay, wherein the clay is characterized by being at least partially exfoliated in the biopolymer binder, or a particle size in a range of about 5 nanometers to about 500 nanometers, or both.   
     
     
         2 . The material of  claim 1 , wherein the biodegradable polymeric structure comprises a homopolymer or a copolymer of monomers selected from a group consisting of lactic acid, lactide, glycol acid, glycolide, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, valerolactone, butyrolactone, caprolactone, and combinations thereof. 
     
     
         3 . The material of  claim 1 , wherein the biodegradable polymeric structure comprises polyhydroxy alkanoate. 
     
     
         4 . The material of  claim 1 , wherein the clay comprises a member selected from a group consisting of smectite, phyllosilicate, montmorillonite, saponite, beidellite, montronite, hectorite, stevensite, vermiculite, kaolinite, hallosite, synthetic phyllosilicate, and combinations thereof. 
     
     
         5 . The material of  claim 1 , wherein the biopolymer comprises a member selected from a group consisting of starch, protein, and combinations thereof. 
     
     
         6 . The material of  claim 1 , further including a topcoat layer. 
     
     
         7 . The material of  claim 1 , further including a top polymeric layer such that the barrier layer is positioned between the biodegradable polymeric structure and the top polymeric layer, the top polymeric layer comprising a homopolymer or a copolymer of monomers selected from a group consisting of lactic acid, lactide, glycol acid, glycolide, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, valerolactone, butyrolactone, caprolactone, and combinations thereof. 
     
     
         8 . The material of  claim 7 , further including an adhesive layer positioned between the barrier layer and the top polymeric layer. 
     
     
         9 . The material of  claim 8 , wherein the adhesive layer comprises a member selected from the group consisting of ethylene vinyl acetate and polyvinyl acetate. 
     
     
         10 . A packaging material, including:
 (a) a paper-based substrate having opposite sides;   (b) a biodegradable polymer layer positioned on at least one side of the paper-based substrate; and   (c) a barrier layer positioned over the biodegradable polymer layer, the barrier layer being derived from a water-based coating composition comprising a biopolymer and clay, wherein the clay is characterized by being at least partially exfoliated in the biopolymer binder, or a particle size in a range of about 5 nanometers to about 500 nanometers, or both.   
     
     
         11 . The material of  claim 10 , wherein the biodegradable polymer layer comprises a homopolymer or a copolymer of monomers selected from a group consisting of lactic acid, lactide, glycol acid, glycolide, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, valerolactone, butyrolactone, caprolactone, and combinations thereof. 
     
     
         12 . The material of  claim 10 , wherein the biodegradable polymer layer comprises polyhydroxy alkanoate. 
     
     
         13 . The material of  claim 10 , wherein the clay comprises a member selected from a group consisting of smectite, phyllosilicate, montmorillonite, saponite, beidellite, montronite, hectorite, stevensite, vermiculite, kaolinite, hallosite, synthetic phyllosilicate, and combinations thereof. 
     
     
         14 . The material of  claim 10 , wherein the biopolymer comprises a member selected from a group consisting of starch, protein, and combinations thereof.